In semiconductor packaging, package substrates, also referred to as interface substrates in the present application, are typically used to interface one or more semiconductor dies to a support surface such as a printed circuit board (PCB). Organic substrates have traditionally been used and continue to be used as interface substrates in a variety of packaging designs, such as ball grid array (BGA) packaging, chip scale package (CSP) solutions, and system-in-package (SiP) solutions.
Organic interface substrates are fabricated according to strict design rules that can raise packaging costs where multiple contact pad pitches are utilized. In addition, the minimum size of interconnect trace line widths, line to line spacing, and contact pad pitch characterizing conventional organic interface substrates can make integration of dies with high density input/output (I/O) arrays challenging.